Ink jet printers create an image on a surface by ejecting ink through orifices in a print head face plate onto a substrate. The print head face plate communicates with a print head reservoir, which communicates with an ink source. Solid ink printers melt ink and deliver the melted ink to the print head reservoir.
The orifices on the print head face plate are quite small and can be easily obstructed by a small impurity in the ink. Therefore, prior to the ink being delivered to the orifice, the ink is filtered in the print head reservoir. Known print head reservoirs include horizontal filters disposed in the reservoir. These horizontal filters resulted in a wide print head reservoir. Accordingly, it is desirable to provide a more compact print head reservoir.
When the solid printer is turned off, the ink that remains in the print head reservoir can freeze. When the ink thaws in the print head reservoir, air that was once in solution in the ink can come out of solution to form air bubbles or air pockets in the print head reservoir. Large air pockets can impede the filtering of the ink as it travels toward the orifices in the print head face plate. Also, air pockets or bubbles can form in other channels that lead to the orifices. These air pockets and/or air bubbles are purged out of the print head reservoir and it is desirable to provide vents in the print head reservoir that can bleed trapped air out of the ink flow path.